code: def get_eikonal_loss(self, grad_theta):
      if grad_theta.shape[0] == 0:
          return torch.tensor(0.0).cuda().float()
  
      eikonal_loss = ((grad_theta.norm(2, dim=1) - 1) ** 2).mean()
      return eikonal_loss
  
file_path: insightface/reconstruction/PBIDR/code/model/loss.py
imports: import torch
  from torch import nn
  from torch.nn import functional
label_desc: Use image node_id 3 for calling the IFLoss obj's underlying member method code with example usage: obj.get_eikonal_loss(grad_theta) and returns: eikonal_loss, torch